The utility model relates to a steady oily technology measure of oil field accuse water for operation medicament inject instrument into, two sections of the instrument are connected with petroleum pipeline post and kit respectively, and the instrument inner wall has the round hole, and by the dissolvability part, the time limits that dissolves of dissolvability part in the preset time, is in encapsulated situation at within the scheduled time instrument inner chamber, can suppress work, after dissolving the part and dissolve, carry out injection work, the medicament passes through in instrument inner wall round hole gets into the instrument ring cavity, the medicament promotes to remove piston motion, compression spring, the sealing drum with remove hinge joint, remove the piston and drive the sealing drum and open the chemical agent impregnation valve, after the injection, instrument inside and outside pressure differential are zero, spring rebound and promote to remove the piston return, and chemical injection valve is closed. The chemical agent impregnation valve can prescribe a time limit locking, one -way injection, open or close in step, deposit for a long time.